1. Field of the Invention
This invention relates to an information recording medium and a process for production thereof. The invention relates particularly, although not exclusively to a reliable information recording medium which is resistant to forgery and a process for production thereof.
2. Related Background Art
To date magnetic recording cards, such as credit cards or bank cards and so on have been used as portable information recording media. In recent years, IC cards, optical cards and so on have been proposed as a portable information media which have a larger recording capacity. Using such a larger recording capacity, it has been proposed to use such media as electric money or bank cards capable of recording dealings with a bank.
In such portable information media which are used to record important information relating to money and so on, it is important that improper use of the media, such as the use of stolen or lost information recording media, is difficult, and faking of the media is also difficult.
One method of preventing faking of a medium, is to provide a picture of the medium owner's face personal data, or data relating to the distributor of the information recording media etc., as holographic information in the information recording medium as initial information before distribution of the medium.
In order to produce such a medium, various methods are used in order to create difficulties in faking the information on the recording medium. For example it is known to form the above mentioned initial information on a thin sheet and attach the sheet to a card. In addition to providing such initial information, a lot of media processing is used for the purpose of preventing fake media. For example in a laminate type card in which a transparent sheet is laminated on an information sheet, it is possible to insert a watermark or special microprint.
In particular where such an information recording medium has a large recording capacity intended for extensive use, if the information recording medium is faked, the social effect is forecast to be very large.
Therefore in such an information recording medium, it is necessary to provide information which is more difficult to fake in order to prevent faking of the information.